Load Pull
Understanding Load Pull
Load pull measurements use mechanical or electronic tuners to sweep the load impedance while measuring output power, PAE, gain, and adjacent channel power. The results are plotted as contours on the Smith chart showing constant performance regions.
Source pull varies the input impedance and is often combined with load pull for complete characterization. Active load pull systems use signal injection to synthesize impedances beyond the passive tuner range, enabling characterization at harmonic frequencies.
Frequently Asked Questions
Why is load pull important for PA design?
Power amplifiers deliver maximum power and efficiency at specific load impedances that differ from 50 ohms. Load pull identifies these optimal impedances for matching network design.
What equipment is needed for load pull?
A load pull system includes programmable impedance tuners, a signal source, power meters, and a spectrum analyzer, all controlled by software.